IRA FLATOW: This is Science Friday. I’m Ira Flatow. A bit later in the hour, how climate change may be killing more fish and why we might be facing a looming sulfur shortage. Plus, we drop in on a herd of goats chewing away some invasive species.

But first, as the new Omicron specific booster shots for SARS-CoV-2 unroll nationwide, new research on the long-term consequences of COVID suggests another reason to avoid infection. A team writing in Nature Medicine describes finding a large proportion of heart problems in patients recovering from COVID even months or even a year later. Here to explain more, Maggie Koerth, science journalist for FiveThirtyEight. She joins me from Minneapolis. Welcome to Science Friday. Welcome back, Maggie.

MAGGIE KOERTH: Thank you so much. I’m happy to be here.

IRA FLATOW: Nice to have you. Let’s look at this, Maggie. What kinds of heart problems are we talking about?

MAGGIE KOERTH: Yeah, so we are talking about things like palpitations, chest pain, shortness of breath. A small minority of people in this study were experiencing more serious things like fainting. And this is out of 346 previously healthy people who were followed up with over the course of about a year after they had a COVID infection. The study found that 73% of them had these symptoms about three months after infection. And 57% were still showing signs of these kind of complications a year after COVID.

IRA FLATOW: That is amazing. Do we have any symptoms that we could look out for?

MAGGIE KOERTH: The symptoms that we’re talking about, we’re talking about things that would be noticeable. Your heart is racing, or you’re having chest pain or shortness of breath. But I think what was really interesting is that when they put these people also through blood markers and MRIs, what they were finding is that they were suffering from inflammation of heart tissue. So this is something that you’re having external symptoms of, but it’s also something that is happening inside.

IRA FLATOW: Huh. Did it matter if people were vaccinated or not?

MAGGIE KOERTH: We don’t know. These screenings were all happening between April 2020 and October of 2021. So people in the study were getting vaccinated during that time. But because some of them had gotten vaccinated after their infection, some had gotten vaccinated before, there just wasn’t a good baseline to do that kind of research from.

IRA FLATOW: And age or gender, any differences?

MAGGIE KOERTH: A large proportion of them were women. And this was also a thing that was happening in people who are fairly young. This is not something that people were suffering from who were older and more likely to have COVID complications to begin with. The average age was around 43.

IRA FLATOW: Wow. So this tells us something about long-COVID and maybe sets up more of a red flag for it than we were talking about before.

MAGGIE KOERTH: Yeah, heart issues, these are just one of some 200 different symptoms that have been connected to long COVID as a syndrome. Part of the mess that we have here is just trying to figure out what is happening, what is likely, how many people have it. And those estimates are still all over the place. So you have some studies that are saying like 30% of people are having symptoms of long COVID 24 weeks after infection. And some studies say up to 70% in that same time period.

IRA FLATOW: Wow.

MAGGIE KOERTH: And you’ve got this new study out of China that found 55% of people having at least one symptom two years after infection. There’s a freelance journalist named Leah Shafer who has a great piece right now in the proceedings of the National Academy of Sciences. And it kind of sums up a lot of what’s going on with this long COVID research because one of the big takeaways right now is that science is still getting its head wrapped around this thing.

IRA FLATOW: Right, right, well, we’ll have a link to that story on our website. Let’s move on to another story. Last week, we talked about the scary sounding phenomenon of the zombie ice in Greenland. But you have an update on a different story from the other side of the world, the so-called doomsday glacier Thwaites in Antarctica.

MAGGIE KOERTH: These all have such cinematic names, don’t they?

IRA FLATOW: [LAUGHS] Yeah. Tell us about that.

MAGGIE KOERTH: Well, Thwaites Glacier is a massive hunk of ice that just kind of hangs off the side of Antarctica. It’s rooted to the sea floor, not onto the land. And it’s about the size of Florida. So if it all completely melted, it could raise sea levels by as much as 10 feet. And already, this one glacier’s melt accounts for 4% of annual sea level rise. So this is something that scientists are paying attention to pretty intensely.

And when we say doomsday, we are talking about its size. We’re talking about the risks that it could pose. We’re not talking about an immediate threat. And one of the things they found out recently by looking at these ridges that were left in the sea floor by movement of the glacier kind of going up and down with daily tidal rise and fall, is that there was a 5 and 1/2 month period that could have happened as recently as mid 20th century, when this thing was retreating at a rate double of what has been observed in the most recent years.

IRA FLATOW: Really?

MAGGIE KOERTH: Yeah, so we know that it can melt much faster than it is right now. The good news is it is not melting that fast right now. But scientists have also documented in recent years that this thing is being hollowed out from below because, again, it’s sitting kind of right on the water. And as that water warms, it’s intruding into the base of the glacier. So in 2019, they found a cavity the size of Manhattan on the underside of this thing.

IRA FLATOW: Oh, wow.

MAGGIE KOERTH: Yeah, and they’re really worried that it could break away from the Antarctic coast in just a few years.

IRA FLATOW: Wow, that’s incredible. It seems like, call it a doomsday glacier because if you get a 10-foot sea level rise, it’s going to be doomsday for a lot of people living on the shorelines of places.

MAGGIE KOERTH: Well, and a lot of the world’s population does live on the shorelines of places.

IRA FLATOW: Yeah. Let’s stay on the ocean for a moment because you have a story about the genetics of an animal called the immortal jellyfish. Is it really immortal?

MAGGIE KOERTH: Kind of. If their body gets sufficiently damaged, these jellyfish can just turn back into a baby and grow again. Now, they are still edible, of course, and they could also be injured in ways that can lead to death. So they’re not completely immortal. But they don’t have to worry about the slow decline of old age. And that naturally makes them really interesting to a certain intelligent species that does have to worry about the slow decline of old age.

IRA FLATOW: Who could that be, I wonder.

MAGGIE KOERTH: Yeah, I know. And scientists have gotten this better understanding of what’s going on in the genes of these jellyfish as they regrow now. So they went to the coast of Italy. They captured some immortal jellyfish. They triggered this rejuvenation process by withholding food. And as these jellyfish were shrinking back into little balls and starting to regrow, the scientists were taking samples at each stage, mushing them up and extracting RNA to study what’s changing genetically during that time.

One of the things that they’re sort of finding is that there’s not a single gene governing immortality in these jellyfish. That it’s more that there are duplicates of some genes, including ones that repair DNA. And they’re turning genes on and off at different stages. So the genes associated with pluripotency, which is the ability of baby cells to grow into lots of different adult cells, instead of just one kind of cell, those go dormant as this animal ages, just like ours do. But then they can kick back on when it’s time to regrow.

IRA FLATOW: Wow, it’s the Benjamin Button of jellyfish.

MAGGIE KOERTH: Kind of, yeah.

IRA FLATOW: Kind of. Another gene story is out there about something else that floats around but in zero gravity. And I’m talking about astronauts and genetic changes in astronauts. Tell us about that.

MAGGIE KOERTH: Yeah, so scientists took these decades old blood samples from astronauts before they flew in space and after they had. And these are from people who flew on the space shuttle between 1998 and 2001. And they’re finding that basically everyone who goes up comes back changed in some small way. Now, these were not big alterations. The scientists don’t think anyone’s long-term health is likely to be threatened.

But it shows that exposure to radiation in space has an impact. And it has that even on young, exceptionally healthy people, like the people we send into space. And these changes that we’re seeing in these samples, they’re kind of things you’d expect to see in adults who are a lot older than the astronauts were. The median age was 42 in these samples. And they’re showing genetic mutations that you would expect in elderly people.

One of the things that the scientists say that we’re really taking away from this is that anybody who’s going into space for these long stretches for these moon bases, for these trips to Mars, they’re going to need detailed regular health screenings. And we’re also going to need to make sure that we are limiting the amount of time you’re in space based on age.

IRA FLATOW: Yeah, well, we haven’t figured that one out yet either, have we? So.

MAGGIE KOERTH: No, thankfully, that is not yet actually a serious immediate problem. But it’s, yeah, more something to look forward to.

IRA FLATOW: One more piece of news– and this one is really interesting– human amputations were successfully done thousands of years earlier than we thought they were. Does this count as good news?

MAGGIE KOERTH: If you are an ancient human who needs your foot amputated, yeah, this counts as great news. So the idea that used to be around is that medicine emerged alongside agricultural societies. And previously, the oldest evidence of amputation that we had was a 7,000-year-old skeleton of a Neolithic farmer in what is now France. But researchers found a skeleton in Borneo that appears to have had a foot amputated and lived to tell about it, and it happened 31,000 years ago.

IRA FLATOW: Wow. How do we know that this actually happened?

MAGGIE KOERTH: So, OK, this is pretty cool. So these researchers, they went and consulted with doctors and scientists who actually study amputation and bone growth after amputation and what happens to your body in the wake of that. And they took this skeleton with its whole lower left leg was completely gone. And there was this kind of bony growth that was left at the place where the limb was missing.

And the scientists that study bones now were able to say, this looks like what happens when you surgically cut a limb. And it’s different from what you see with an accidental limb loss. So it suggests that this was not just like somebody that got their foot trapped in something or that got it eaten off by a saber tooth tiger. This looks like actual intentional cutting and what the healing process looks like after that. And because of how much growth is on that bone, it also suggests that person lived for at least six years after they lost their foot.

IRA FLATOW: Wow. And of course, we don’t know what happened to the person after he or she lost that foot, so.

MAGGIE KOERTH: No, we don’t know. But we do know that there’s no sign in the bone of infection, which is also a really big deal because that implies, not proof, but it implies that whoever was doing this amputation also knew something about how to use the plant biodiversity around them to prevent infection.

IRA FLATOW: Well, I hope they learned how to use the plant biodiversity around them for anesthetics because I can’t imagine having an amputation without anesthetics. And it’s been done.

MAGGIE KOERTH: It’s been done many, many times, and it does not sound like fun.

IRA FLATOW: Maggie, you always sound like fun Thank you for taking time to be with us today.

MAGGIE KOERTH: Thank you so much.

IRA FLATOW: Maggie Koerth, science journalist for FiveThirtyEight based in Minneapolis.